1. Field of the Invention
This invention relates to a bushing for use with a grinding abrasive flap wheel having interleaved coated abrasive flaps.
2. Prior Art
Flap-type rotary abrasive devices having annular arrays of flexible abrasive leaves are commonly used in the abrasive finishing art. For economic reasons, conventional rotary abrasive devices consist of flexible leaves each comprising a piece of sheet material having abrasive particles bonded on one face thereof.
Fabrication of such a rotary device conventionally requires that the abrasive leaves have two notches in their opposite side edges near the base end of each leaf. As the leaves are arranged in an annular array, the notches form concentric circular depressions on opposite sides of the array.
Circular disks such as two metallic end caps mounted on opposite sides of the array are provided serve as reinforcement for the arrangement of leaves. Each end cap has an inwardly extending lip which engages the circular depressions thereby mechanically gripping the inner ends of the abrasive leaves. An adhesive is commonly introduced into contact with the leaves at their base ends to bond them into a unitary core.
The design of abrasive configurations has varied somewhat, but the basic elements remain similar for manufacturing and cost reasons. A significant problem which exists with such abrasive flap devices is that the flaps tend to blow out prematurely during use. This is typically due to a slight bowing in the flaps which results from pressure exerted on a bearing surface surrounding a central opening of hubs of the end caps which over time disfigures the end cap. This effect is illustrated in FIG. 2. Traditional designs run a drive shaft through the hubs of the end caps with the caps being locked in place on the shaft by nut. Thus, the hubs bear significant force during use.
The present invention discloses bushings for use with a grinding abrasive flap wheel. By so providing, the present invention overcomes the deficiencies in the art and further reduces the cost of manufacture of abrasive flap wheels while increasing the life thereof